Electrical apparatus



Nov. 8, 1938. J. L. GREEN ET Al.

ELECTRICAL APPARATUS Filed June 5, 1937 w f l Y R. www E mi w mw .7 wwwZ/U www 4 F 5 )MMX- 3.3M/

ATTORNEY.

I Patented Nov;l 8, 1938y James L. Green, Cleveland, Ohio, and FrederickT. Hicks, Detroit, Mich., assignors to The Indemse Corporation, acorporation oi.' Michigan ,Application cime s, 193i, serial ivo. 146,614

Y11 chants.` (o1. ris-36s) Our invention pertains to electricallyoperated contactless vibrators and systems for operatin and utilizing,the same. y A

It is an object of our invention to provide electro-magneticallyoperated vibrators which' are especially useful as radio B power unitsforenergizing luminous signs, producing musical tones, and musicalnotes, as frequency standardsand for many other applications requiringlong life and permanent adjustment by eliminating me,- chanicallyengaging contacts with the accompanying wear, clatter, corrosion, andareing.

It is also an object of our invention to provvide a contactless vibratoractuated by'a/coil of a conductive metal which variesits resistance inaccordance with the intensity of the electromagnetic ileld in which itis exposed.

It is a further object of our invention to prqvide such a contactlessvibrator having means for periodically varying the, iield intensitycomprisingI an armature member which is moved by the ux from the windingfor pulsating the field in which the winding is exposed.

Another object of our invention is to provide such a contactlessvibrator wherein the eld structure comprises a vcore and an enclosingshell arranged to deiine seriestconnected air gapsl and having theenergizing winding dis. posed acacent one of the air gaps and thearmature adjacent the other `air gap A further objectief our inventionis to provide such a contactless vibrator comprising a current inverterfor inverting iromdirect current.

The novel features which we consider charac-- teristic of our inventionare set forth with particularity in the yappended claims. tion "itself,however, bothas toits organization and its method of operation, togetherwith additional objects and ,advantages thereof. will best 4a beunderstood from the following description of specific embodiments',vwhen read in connection with the accompanying drawing, in which:

Fig. 1 is a longitudinal sectional view showing the construction ofthecontactless vibrator;

Figa 2 is a. diagrammatic view representing the device in connectionwith `associated circuits for operating and utilizing thesame;

Fig. 3 is a longitudinal sectional .View showing another embodimentofthe vibrator;

Fig, 4 is an elevational view ofthe armature4 support; and

. Fig. 5 is a diagrammatic view owing a sys,- tem utilizing thedevice? yA Referring more particularly to` Fig. 1 of the drawing. our contactlessvibrator comprises a shell I which is of iron or other ferro-magneticmaterial of low magnetic reluctance, of \cast or sheet construction. Theshell I which is pref erably of circular cross-section, is provided atone end with an enlarged annular collar 3 for 5 receiving` andsupporting a cap 5 of magnetizvable material. The collar 3 isv preciselytapered and ground to fit snugly into an annular recess 'I in the edgeof the rim 9 of the cap in order to provide a close coupled magneticjoint.` The 10 outer surface of the collar 3 is threaded forcooperatively engaging the outer wall of the recess I inthe cap, whichis suitably threaded.

The lcap is thusV firmly secured on one open end of the shell I, whereitis a closure and serves to 15l continue the magnetic flux path.

A pole II of magnetizable material is mounted on the inside of theclosed end of the cap and it extends into the shell to' continue thelowreluctance flux path therein. The pole II is sub- 20 stantially ilatatits inner end,l and it may be integral therewith,l or secured thereonas by welding for examplel- An armature I34 is movably supported adja,cent the inner end of the pole II on a spring 25 support, I5 which isclamped between the outerI end of the shell and thev cap. The armature=support comprises a flat resilient diaphragm like member; preferablynon-magnetic, with "apertures to minimize air damping. The armature 30is secured to the support in any suitable manner as by rivetinggandopposite sides ofl the armature are of unlike `c onior1'11ations.v Asshown, the inner side of the amature' I3 lis a tapered cone likeconformation which is cut o' at at the 35 inner end .like a truncatedcone, for a purpose tobe subsequently. described. The shape, size andweight of the armature and the rigidity of its support may be suitablyselected for prede-` termining its vibrating frequency. l 40 Enclosedandsupported by the shell I is a core I9 which/is provided 'with anelectrically conductive coil or solenoid winding 2|, for magnetizingthe. eldstructure ofthe vibrator. 'I'he core fi 9 is covered withl alayer or tube 23 of in'- 45 sulating material and insulated conductor isf woundAV thereon'. The coil is held together` and secured in placeb'yfmeans of suitably insulated annular disks 25 in theV usual manner. Aa flange 21 projects inwardly in the shell for'abut- 50- ting andholding the inner end of the coil when 'l it is inserted into the shell.The terminals 28 of thecoil 2i are extended from the shell tlirough gsuitable bushins #I in the side wall of the shell I`as will beunderstood.

Although the coil or solenoid winding may be Wound on the core andsecured in the usual manner, the electrical conductor which cornprisesthe coil is made of a special metal that provides an importantcharacteristic in the operation of the contactless vibrator, as willsubsequently be more fully set forth.

The end of the core i9 adjacent the amature is provided with a conicalrecess 28 similar in conformation to the adjacent side of the armaturewhich moves therein. g

At its other end the core i8 is recessed axially to receive a pin 3iprojecting from a plug 33 of brass or other non-magnetic material. Beingof a cross section similar to the core I 9, the nonmagnetic plug 33 fitsinto the coil 2i where it serves to secure the outer end of the corespaced from the end of the coil. The plug 33 is on a closure disli 35which closes the end of the shell i in which it is preferably secured byexternal threads engaging corresponding threads on the inside of theshell. The disk 35 is also made of non-magnetic material in order toprovide an appreciable air gap for the magnetic flux to pass through theturns of the'winding 2i between the adjacent ends of the core I 9 andthe shell I.

it will be seen that the held structure of our contactless vibratorcomprises the shell I, cap 5, pole il and core i9 which together dene alow reluctance flux path having two air gaps in series relation as at Aand B. The armature I3 is disposed in one oi the air gaps, at A and itis so mounted that it can move axially therein.

Because of its unliise conformation on opposite sides, corresponding tothe adjacent ileld structure, and because of its interiltting relationthe movement of the armature I3 toward the core |S increases the totalair gap, and reverse movement decreases the total air gap.

Because of the disposition of the solenoid lwinding 2l around the secondair gap B, the coils of the winding are exposed to the varying iiuxpassing between the adjacent ends of the core and the shell.

For winding the magnetizing coil, an electrical conductor is provided ofmetal which varies its resistance according to the intensity oi theelectromagnetic iield to which it is exposed. Such electrical andmagnetic properties are found in cadmium, bismuth, zinc, silver andother metals and alloys in which the resistance increases when theintensityY of the electromagnetic field is in creased. Such metals weterm ohmomagnetic. In our contactless vibrator we expose a coil of suchohmomagnetic material, in the second air gap B which provides themaximum exposure to the varying ux. For this purpose we preferably usebismuth, either pure or alloyed. At times` it is necessary to make onlya part oi' the coil of bismuth in order to limit the resistance inaccordance with the applied D; C. voltage. The frequency of vibration ofthe armature is iniiuenced by the inductance and magnetic lag of thecoilas well as by the percentage of chmomagnetic material.

In use the solenoid winding 2| of the vibrator is connected by inputconductors 31 and 39 for energization from a source of direct currentsuch as a battery 4|. A high inductive impedance such as a choke coil 43may be connected in series with one conductor 3l ofthe energizingcircuit. If the vibrator is to be utilized as an inverter forconvertinga portion of the direct current to an alternating or pulsatingcurrent, loutput conductors 45 and 41 are connected from 'opposite endsof the energizing winding 2|, or tapped from intermediate turns.

To restrict the direct current from the output circuit, and forenergizing the circuit in accordance with the pulsating component of theenergizing current, a condenser 49 is inserted in one output conductor.If the vibrator is to be utilized for supplying only a potential formodulating purposes the condenser may be quite small, but if it is to beutilized to supply a substantial current for power purposes thecondenser must be selected of a suitable size. Transformers or otheroutput arrangements may be utilized if desired.

In operation, the current is turned on to energize the coil 2| and tomagnetize the core I5. Electromagnetic flux is thus induced to flowthrough the iield structure of the vibrator passing across the air gap Ato the pole I I, thence through the cap 5, through the shell I, andreturning from the other end of the shell to the other end of the coreby passing through the surrounding air gap B and the adjacent'turns ofthe coil. The armature is then moved toward the :pole II extending fromthe cap. This happens because of the tendency of magnetic loops toshorten their length, and because of the peculiar shape of the armatureI3 it moves away from the core I9 and toward the pole II to shorten theair gap.

Because of its peculiar non-uniform shape, the movement of the armaturetoward the pole II decreases the total air gap, as previously described.This decreases the reluctance of the flux path and increases the ux. Butincreasing flux also increases the density of the eld, to which thecoils ofthe energizing Winding are exposed in the air gap, and this inturn increases the ohmic resistance of the Winding, which is of anohmomagnetic material, as previously set forth. This decreases theenergizing current in the Winding and the armature I3 falls back fromthe pole II toward the core because of the resilience of its support.

Movement of the armature away from the pole II increases the total airgap A and increases the reluctance of the ilux path, as previously setforth. This causes the flux to decrease which diminishes the ileldintensity to which the energizing winding is exposed in the air gap Baround the left hand end of the core. The resistance of the Winding 2|is thus decreased and it takes a greater energizing current. The iluxnow increases and the armature is again drawn toward the pole II aspreviously described.

This sequence of operations constitutes a cycle which is repeatedperiodically with such rapidity that the armature is caused to vibrate.The growing and collapsing of the ileldinduces an alternating current inthe energizing winding which may be tapped on by an output circuit asdisclosed. Also the winding may be provided with various output taps toprovide induced alternating current of any desired potential.

In accordance with another embodiment of our invention, as shown in Fig.3, two coils I and 53 may be mounted in end-to-end relation for deiiningan air gap C between the cores 55 and 51 which are disposed in axialalignment. The right hand coil 5| is wound with ordinary copper wire andthe left hand coil 53 is wound with a conductor of bismuth or otherohmomagnetic material. The two coils may be selected in various ratiosof resistance, turns, and the like according to the operatingcharacteristics desired and f they are wound and secured upon the coresin the usual manner.

istics for current 'inverter 'use are obtained by providing about tenper cent greater ampere turns on the left hand coil Slthan on the coppercoil i. A slack conductor 5t connects adjaacent ends oi the coils 5i and5t.

The inturned ends ci the cores are respectively square and conicallyrecessed, as in the first embodiment. At its outer end, the right hand'core 5| is integral or joined on the closed end ol a Desirable operatingcharactercup shaped shell 59 which is provided with a threaded couplingcollar Si around its open end. The outer end'oi the left hand core 5l isapertured. to ilrmly receive a pin 63 projecting from a plug ofnon-magnetic material. I'he outer end of the non-magnetic plug 65 isprovided` with a reduced portion 6l which is threaded for se-r. curementin the closed endof a cup shaped shell 69 which has a threaded collar ilaround its open` edges.

The shells- 59` and 69, which venclose and support theirrespectivsolenoids, are of any suitable ferroLmagnetic material and theyare firmly joined together around' their open edgesl by a .couplingsleeve 'i3 which is internally threaded for clamping the couplingcollars. 'I'he sleevel 'i3 is also of ferro-magnetic material and servesto provide (a joint of low magnetic reluctance. The armature 'l 3,similar to that previously described, is supported arounditsjouter edgesin an annular recess '15 in the abutting edges of the shells whereby itis disposed in the air gap C between the inner endsol' the cores.` andas in the first embodiment the amature diaphragm has aper-1v tures tominimize damping. lInterconnecting conductor Slis passed through one ofthe apertures, as shown in Fig. i.

A terminal conductor 11 extends from the outerl end of theohmomagneticcoil 53 through a suitable bushing i9 in theside wall of,theshell. f

From the outerend oi' thecopper coil 5i, and alsoffrom an intermediateturn, a terminal oo nductor 8l and an intermediate tap 83 arerespectively connected passing through suitable insulating bushings Inoperation the terminal conductor 'il from I the ohmornagnetic coll 53 isconnected to a direct current source, such as the batterv tl', as shownin Fie. 5. The intermediate tap 83 fromythe' con per coil di connects tothe other side of the hatn To energize an output circuit in accordancewith the pulsating con'iponentoi'r the input currenty the terminalconductor iii may be connected through a condenser 8d to an out-putconductor lili. The other output conductor Si is connected from theterminal conductor 'il of. the other coll. This embodiment or ourinvention operates in a manner substantiallysimilar to the operationdescribed and will not he repeated. l

In the operation' of this embodiment the auton transformer actionprovides a, higher out-out voltage in proportion tothe input voltage.Also, copper coil ushells may, be provided having different tapconnections, resistance, Aand ampere turns for .convenient replacementand attachment to the ohmomagnetic half of the unit.

By eliminating mechanically striking contacts and operating our devicein the manner disclosed,

the vibrator is free from mechanical wear, sparking and corrosion whichwould change its adjustment and shorten its life. j Also disturbinginduences are eliminated such .as the noise caused 'of the firstembodiment which was previouslyl bythe mechanical striking of contactsand electro-magnetic disturbances caused, by sparking. 'I'he vibratorisfree to move with a pure simple harmonic motion, as determined by ,theweight and elasticity of the armature, as Welly as the inductance ol:`the coil and other factors; as previously set forth our contactlessvibrator is especially useful asa/radio E supply unit, in luminous signlighting, as a frequency standard or modu 'lating device and for allpurposes where long life and permanent adjustment are important.

lil

-We do not wish to be restricted to the specific Y structural details,of parts or circuits herein set forth, as various modications thereofmay7 he.

eiected without departing from the' spirit and scope of our invention.

We claim: y

l. A contatless vibrator comprising, e. deld structure of magnetizahlematerial deilning an electromagnetic hun path of low `reluctance havingan air gap therein, 'an electrical conductor ol ohmomagnetlc materialdisposed forenergising said field structure and exposure to the huntherefrom, and an armature of magnetizalole material movable for varyingsaid air gap and responsive to the ux therein.

2. A contactiess vibrator comprising, a held structureel magnetiizablematerial 'having air.

amature ci magnetizable material adjacent the` other air gap fordecreasing the tctal'air gap in Aresponse to increasing hun, and aresilient support for movably supporting` said armature.

. d. l contactless vibrator comprising, a held structure ci?ferro-magnetic material having air gaps therein, an electrical conductoroi? llisnfluth disposed adjacent one of said air gaps lor magnetizingthe field structure Aand exposure to the hun therefrom, and amagnetizable armature movable adjacent the other air gap.Y ior varyingthe'total air gap in response to the'varyinayduc `density` therein.

5.. A contactless vibrator comprising, a maislo netizable .structurehaving an airV gap, the portions ci the field structure on oppositesides ot lsaid air gap being of unlike conformation, an electricalconductor' for magnetizing said held structure, an armature member oAunlilre conformation on opposite sidesy corresponding to the unlikeconformations of the portions of the ileld structure' spaced adjacentsaid air gap, and resilient means for movahly supporting said arrria-lture' adjacent the air gap with its unlike conformations toward the heldstructure surfaces of corresponding conformation.

r `il. Acontactless vibrator comprising, a core oi ferro-magneticmaterial, a winding of ohmoinagnetic materialA for energizing said core,a shell of ferro-magnetic material enclosing said core,

ya ferro-magnetic cap secured on one end of said y f shell, aferro-magneticpole extending frein.4 said cap into said shell in spacedrelation to derine'an saidcore, and the air gap at the adjacent end ofspaced ends of said core and said pole being of unlike conformation, anarmature disposed in said air gap, said armature being of unlikeconformation on opposite sides corresponding to the unlike conformationsof the spaced core and pole dening the air gap, and resilient means formovably supporting the armature in said air gap.

7. A contactless vibrator comprising, a pair of cores of ferro-magneticmaterial, an enclosing shell of ferro-magnetic material for supportingsaid cores in spaced end-to-end relation with an air gap therebetween, awinding of copper conductor on one of said cores, a Winding of bismuthon the other one of said cores, an armature movable in response tomagnetic ilux from said cores for varying the total air gap, and meansfor movably supporting said armature adjacent the air gap:

, 8. In combination, a solenoid winding of onmomagnetic material, asource of direct current, a. circuit for energizing said Winding fromsaid source, a eld structure having a flux path magnetized by saidWinding, and means for varying the reluctance of said path to subjectsaid Winding to a varying flux for varying the resistance of saidWinding in said circuit.

9. A contactless vibrator system comprising, a solenoid winding ofohmomagnetic material, a source of direct current, a circuitAIorenergizing said Winding from said source, a iield structure having a uxpath magnetized by said winding, i

and an armature responsive to flux in said path for periodicallydecreasing the reluctance of the path whereby the varying flux variesthe resistance of the Winding and the armature vibrates. 10. A currentinverter system comprising, a eld structure providing a low reluctanceilux path, a winding of bismuth for magnetizing said iield structure, asource of direct current, an input circuit for energizing said windingfrom said source, means for periodically varying the reluctance of theilux path to pulsate the energizing current, an output circuit, andmeansfor energizing said output circuit in accordance with the pulsatingcomponent of said energizing current.

11, A current inverter system comprising, a eld structure providing alow reluctance ux path, a winding of ohmomagnetic material formagnetizing said field structure, a source of direct current, an inputcircuit for energizing said winding from said source, an armatureresponsive to the flux for varying the reluctance of the ilux path, saidarmature moving to decrease the reluctanceof the ux path in response toincreasing flux whereby the armature moves periodically, an outputcircuit, and means for energizing said output circuit in accordance withthe pulsating component of said energizing current.

JAMES L. GREEN. FREDERICK T. mons.

